Factors controlling the oxidation of long-chain fatty acids will be investigated. L-carnitine is an obligate substrate in long chain fatty acid oxidation. Carnitine is derived from trimethyllysine probably originating from protein-bound lysine. We are studying the metabolic pathway from trimethyllysine to butyrobetaine (trimethylaminobutyrate) and carnitine. An intermediate has been isolated and will be chemically characterized. The enzymatic pathway for the formation of this intermediate and its further metabolism to butyrobetaine will be investigated. The turnover of protein-bound trimethyllysine as a precursor of carnitine will be studied. Conditions will be examined that alter the turnover of carnitine. Analytical methods will be developed using high pressure liquid chromatography and gas chromatography to quantitate the trimethyllamino-compounds involved in carnitine biosynthesis and degradation. Ion-pair chromatography will be evaluated. The possible existence of isoenzymes of canitine palmitoyltransferase will be examined and microanalytical assays developed. The content of hepatic mitochondrial fatty acid oxidation in normal animals will be compared to the state of decreased fatty acid oxidation observed in riboflavin deficiency. The factors in influencing the mitochondrial concentration and compartmentalization of coenzyme A will be undertaken. The protocol involves the development of analytical methods to allow assessment of the factors controlling fatty acid oxidation in in vitro and in vivo animal model studies and, in addition, monitoring of clinical situations in humans.